My prostate. I was just in the show jacking off and wondered how it would feel to cum by rubbing my prostate but I am not sure where it is. I put my middle finger up my ass and working it in and out and it felt good.
You should be able to feel your prostate about two inches in and toward your belly. It is often a walnut-shaped bump. Some can feel it some can't. Also try masterbating a bit before hand.. it well swell up and make it more noticable.
If, when you're masturbating, you apply pressure to the perineum (the continuance of the penile tissue between the scrotum & the anus), you should find a point which is particularly sensitive to pressure. This is the location of the prostate gland inside the anus. However, I've never been able to successfully stimulate the prostate manually, either by myself, or by anyone else. The only time anything's happened is when I've been penetrated anally, at which point I climaxed with a major orgasm, without even having an erection (most men lose their erections as soon as they are penetrated).